Dynamo-electric machine



(ModeL) 2Sheets-Sheet L r E. THOMSON. Dynamo Electric Machine.

Patented Oct. 5,1880.

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I 2 G G H F INVENTORI WITNESSES:

ILFETERS, FHOTO-UTMOGRAPHEH, WASHINGTON. D C.

.(ModeL) 2 Sheets-Sheet 2.

E. THOMSON; Dynamo Electric Machine. No. 233,047; Patented Oct. 5,1880.

" Q RE FIG.9.

WITNESSES: INVENTOR'.

NPEFERS, PHOTO-LITHOGRAPMER, V/ASHINGYON o c UNITED STATES PATENTOFFICE.

ELIHU THOMSON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO AMERI- CANELECTRIC COMPANY, OF NEW BRITAIN, CONNECTICUT.

DY NAMO-ELECTR IC MACHINE.

SPECIFICATION forming part of Letters Patent No. 233,047, dated October5, 1880.

Application filed May 4, 1880. (ModeL) To all whom it may concern:

Be it known that I, ELIHU THOMSON, residing in the city and county ofPhiladelphia, Pennsylvania, have invented certain new and usefulImprovements in Dynamo-Electric Machines,whereby a very highelectro-motive force is obtained with the advantages of lightness,compactness, and durability; and I do hereby declare the following to besuch a description of said improvements as will enable those skilled inthe art to make and use the same.

In United States Patent No. 2l9,l57, dated September 2, 1879, to Houstonand Thomson, accessory magnetizing-coils surrounding the I 5 armatureand operating in conjunction with the field-magnet coils in polarizingthe armature are described.

One of the objects of the present invention is to combine in a singlecoil the functions of the accessory coils with those of the field-magnetcoils of said patent, and thereby secure simplicity and ease ofconstruction. This is accomplished by winding coils upon thefieldmagnets shaped in conformity thereto, so as to inclose saidmagnets, and also, as far as practicable, to inclose the armature, whichrevolves between the poles, as hereinafter to be described.

Another object of the presentinvention is to 0 provide a form offield-magnet frame which shall fully utilize both the internal andexternal magnetizing effects of the field-magnet coils. To this end thefield-magnets, instead of simply being inclosed by themagnetizing-coils,

3 5 have extensions,which serve,in turn, to inclose said coils, in themanner as hereinafter described.

Another object of the present invention is to provide an armature fordynamo-electric machines all parts of the insulated wire of which shallat all times be under the direct influence of the field-magnets, andthus avoid the use of inactive wire, increase the electro-motive forceof the currents generated, and reduce to a mini- 4 5 mum the length ofwire necessary to generate a given electro-motive force.

Another object of the present invention is to provide an armature fordynamo-electric machines the magnetizing effect upon which shall not belimited to the point of magnetic saturation of the field-magnets, butshall be further reenforced by the direct action upon the iron core ofsaid armature and the insulated wire surrounding the same of thecurrents traversing the whole of the field-magnet coils, which coils aremade to inclose and surround the revolving armature, so that the ironcore of the armature becomes practically but a movable extension of thefield-magnet poles themselves.

It will be understood by those versed in the art that variousmodifications of the forms and disposition of the parts from those to bepresently described maybe made without affecting the essentials of theinvention itself, it being here purposed to describe a typicalarrangement of parts that has been found very successful in practice.

Figure l is a side elevation, partly in section, of a machine embodyingmy improvements. Fig. 2 is an end elevation of the same. Fig. 3 is a topview or plan of the same. Fig. 4 is an axial view of a form ofarmature-core adapted to use in the present invention. Fig. 5 is a sideview of said armature-core. Fig. (3 is a section of said armature'coreparallel to the axis of rotation. Fig. 7 is an axial view of a form ofarmature winding adapted to use in the present invention. Fig. 8 is alateral view of the armature winding. Figs. 9, 10, 1.1, and 12 aredesigned to elucidate the manner of oper- 8o ation and the principlesinvolved.

In Fig. 1, N is a hollow shell or cylinder of iron, (which may, however,in certain cases,be solid,) constitutin gone pole of the field-m agnet.Its outer edge, F, is flanged, and its inner face, H H, shaped toconform to the rounded outline of the armature of the machine, as shown.An opening or openings through the face H H are provided, as shown at O,to allow circulation of air through the center of the shell N. A 0similar shell of iron, S, is placed opposite to N, it being alsoflanged, as at F, and constituting the opposite pole of thefield-magnet. Bars or masses of iron B B B B, &c., join the flanges F F,being preferably inserted in holes 5 in the latter, and are sufficientin number and size to make thorough magnetic contact between the flangesF F.

Coils C C and C C of insulated wire surround the fleld-magnet poles Nand S, and also Ioo the armature of the machine, and serve for thedirect magnetization of said poles and of the armature-core itself.

Rings R It, of metal or other suitable material, may be provided to keepthe coils G and O O in place, since in most cases they project beyondthe poles N and S.

The coils O G and O G can be united into a single continuous coil,extending from one flange, F, to the other, F, if openings are providedfor the passage of the shaft of the armature.

The electric current sent through the coils O G and (3 O is in the samedirection in both coils, and may be derived either from the machineitself or from any other suitable source.

The bars B B B B, 860., are situated near the outside of the coils (J Gand O O, and are therefore magnetized by said coils, the direceration ofwhich are to be hereinafterdescribed.

In Fig. 1, J represents a portion of the arm supporting the journals ofthe shaft of the armature. ff' are the feet of the machine.

In Fig. 2 similar parts to those in Fig. 1 are designated by similarletters of reference. The commutator is shown at K, and thedrivingpulley at P. In Fig. 3, also, similar parts to those in Fig. 1are designated by similar letters of reference.

The armature employed in the present invention is preferably ofsphericalform, it being found to possess great advantages over other forms. I donot confine myself to an armature of spherical shape, but may shape thefield-magnet poles so as to make use of other curved formsa prolate oroblate spheroid, an ellipsoid of revolution, or figures of armature, theoutlines of which are partly curved and partly straight, the mainrequisites being that the armature shall permit of almost completeinclosure by the field-magnet coils, and that the wire and iron of saidarmature shall not present too great inequalities of surface to thepoles of the field-magnets.

The core of the armature may be made in a variety of ways, the necessarycondition being that it contain sufficient iron for thoroughmagnetization, and that the iron be sufficiently subdivided to preventthe circulation of local currents in it. i

Fig. 4 shows a form of armature-core employed to obtain a sphericaloutline in the armature when wound with its insulated wire. Fig. 5 isthe same seen from the side.

Two plates, D D, fastened to the shaft X, and perforated or otherwiseprovided with slits or openings to a, Fig. 4, are set at such a distanceapart as to leave space between them for the It'must be understood,however, that winding of soft-iron wire or strips to a spherical form,W, Figs. 4. and 5. The core, which thus presents the form of a sphereflattened at those portions where the axis X enters, is afterward woundwith insulated wire to the outline shown by dotted lines, Fig. 5. Fig. 6shows the same core in section, the central portion being left hollow,as shown, while the iron wire W is supported in a suitable manner toform a hollow curved shell.

Instead of the iron wire W, rings or bars of iron which, when fittedtogether, give the required outline, may be used.

Considerable latitude in the construction of the armature-core used inmy invention may be exercised, since said core is not alone dependentfor its magnetization on the induced magnetism from the field-magnetpoles, but is directly magnetized by the field-magnet coils themselves.

With the form of armature-core described it is not difficult to windupon it insulated wire so as to obtain a nearly spherical outline. Thenumber and connection of the coils on the armature will vary accordingto the form and arrangement of the commutator or the purpose to whichthe current developed is to be applied, and it is not intended,therefore, to limit the present invention to any particular arrangementof the coils on the armature. I find, however, the winding andconnection of coils described in United States Patent No. 223,557, datedJanuary 13, 1880, to Thomson and Houston, to be well adapted to theconditions of operation of the present invention, and will thereforetake it as an example in further describing my invention.

Fig. 7 shows a spherical armature provided with three coils intersectingone another near the axis X. The manner of winding said coils to secureequality in lengths of wire and uniformity of outline is substantiallyas follows: First, one-half of the wire of one of the coils is wound onthen, second, one-half of the wire of the second coil; then, third, thewhole of the wire of the third coil is wound; then, fourth, theremaining half of the second coil, and finally-the remaining half of thefirst coil, so that equal portions of the first coil respectivelyunderlie and overlie the other coils where they intersect, and equalportions of the second coil underlie and overlie the whole of the thirdcoil inilike manner. The connection of the three coils so wound is made,as before stated, in accordance with Patent N 0. 223,557 before referred to, and a suitable commutator, K, consisting of three insulatedcopper segments, is provided and mounted on the shaft in accordance withsaid patent. If the armature be run for reversed currents, nocommutation is, of course, necessary, but the ends of the armature-coilsare carried out in the manner usual in such a case.

In the drawings the connection of the conductors of the machine into acircuit is not shown, as it admits of several unimportant IIOmodifications well understood by those versed in the art, and virtuallyshown in the previous Letters Patent before referred to.

The commutator-brushes being positive and negative, respectively, thecurrent may be sent through the magnetizing-coils O O and O G in seriesor in multiple are, according to the size of wire used in winding them.Single, double, &c., windings may in like manner be used. Fig. 9 is anoutline section intended to elucidate the distribution of magneticpolarity in a machine constructed as hereinbefore described. Thearmature-core W receives an inductive action from all directions, asindicated by the arrows converging upon it from the concave sphericalsurface of the magnet-poles N and S. It will thus be seen, also, that noportion of the wire surrounding the core 7 can escape the powerfuldirect action of the field of force from the poles N and S. In allmachines hitherto produced a considerable portion of the armature-wirehas escaped this direct action. In the Paccinotti, Gramme, and similarmachines it is the wire in the interior surface of the ring which thusescapes. In the SiemensJVeston, and similar machines it is the wire thatpasses over the ends of the cylindrical core, and from the overlappingof the numerous coils at the ends of the cylinder this inactive portionis made to bear a very considerable proportion to the rest or activeportion.

In Fig. 10 an outline section of a cylindrical armature as commonly usedis shown, where N and S are the poles of the field-magnets. The portionsof armature-wire at e e e c in dotted lines do not at any time comeunder the action of the field-poles N and S.

To reduce the loss due to inactive wire 6 e e c to a minimum, acylindrical armature whose length is relatively several times itsdiameter is commonly employed, giving rise to inconvenient form ofmachine and diffusion of magnetic field. Moreover, there is noconvergence in all directions of the magnetic force upon the armature,the arrows, Fig. 10, showing its distribution, being sensibly parallel.

In Fig. 9 the distribution of the magnetic polarization induced by thecoils G G and G 0, both in the poles N and S and in the connecting-barsB B, B B, is shown by arrows, both inner and outer sides of themagnetizing-coils being utilized. This feature enables greatconcentration of magnetic force to be obtained.

Besides the convergence of the field of force upon the armature in alldirections, there is yet to be considered the direct magnetizing andinductive action of the coils O G and O G upon the whole of thearmature-wire.

In Fig. 11 the coils G O and O O are alone supposed to surround. thearmature-core A, which, with its Wire coils, revolves. A powerfulcurrent is sustained in the coils G G and O G from a suitable source ofelectricity. The armature being revolved, currents of considerablestrength are induced in the coils of said armature, which result mainlyfrom the effect of the coils 0 0 and C O in giving polarity N S to thearmature-core, and also from direct induction of the stationary-wirecoils upon the moving arn'iatnre-coils. Indeed, it would be sufficientto revolve only the coils of the armature and allow the core itself toremain stationary, but the practical difficulties of construction arethereby increased.

In illustration of the direct inductive action of the magnet-coils uponthe armature-coils reference is made to Fig. l2,where a coil, G (3,through which a current is circulating, is crossed transversely by ashaft, X, bearing several wire hoops, whose planes pass through the axisof rotation and are at angles with one another. If this arrangement berevolved, currents are set up in the wire hoops, due to direct inductiveaction of the currents in the coil C O.

In my present invention the same coils that give magnetism to thefield-magnets are made to fulfill, in addition, the other functions, asabove described, at the same time that all the wire of the armatureis'nseful in generating effective current, being placed constantly underthe influence of the field-magnets and field-magnet coils.

Besides many advantages from an electrical and economical point of view,my invention possesses several mechanical advantages.

From the fact of the complete inolosure of the armature by themagnet-frame, injury to it by objects being brought into contact with itwhile it is revolving is avoided. The fieldmagnet poles, also, beingthoroughly inclosed, cannot attract masses of iron inadvertently leftnear the machine, and thereby become injured. The external iron of themachine serves also as an effective protection to the magnet-coils,preventing injury during shipment or otherwise.

I claim as my invention 1. In a dynamo-electric machine, a set of twomagnetizing-coils directly surrounding both the field-magnets and therevolving armature of the machine, for the purposes speci fied.

2. In a dynamo-electric machine, a set of two magnetizing'coils, whichmay, if desired, be combined into a single coil, as described, directlysurrounding the iron cores of the fieldmagnets and also the revolvingarmature, and constituting the sole source of magnetic field andinductive action in the machine.

8. In a dynamo-electric machine, magnetizing-coils G O and G U,inclosing and surrounding the field-magnet poles N S, and in turnsurrounded and inclosed by iron bars B B, or plates of iron uniting saidpoles externally, the whole arranged for the purpose of utilizing theinternal magnetizing effect of said coils upon said poles, and alsoexternal magnetizing effect of said coils upon the bars B B, asdescribed.

4. In a dynamo-electric machine, an armature-core of spherical orsimilar outline, flattened at the parts where the shaft enters, placedbetween poles N and S of field-magnets, also shaped to a correspondinghollow spherical or similar outline, the shaft of said armature-coreoccupying a position transverse to that of a line joining the centers ofsaid magnet-poles, as described.

5. In a dynamo-electric machine, an armature-core of spherical orequivalent outline, as described, placed between the poles N S of thefield-magnets, as specified, said'core to be inductively magnetized by aconvergence upon it from all sides of the lines of magnetic force fromthe field-magnets, and at the same time to be directly magnetized by thecoils of the field-magnets surrounding and inclosing said armature-core.

6. In a dynamo-electric machine, an armature-core wound with insulatedwire toa spherical outline, or nearly so, inclosed and surrounded as faras practicable by the field-magnet poles, except at the gaps or spacesseparating said poles, and revolved upon an axis which is transverse tolines joining the fieldmagnet poles, or which axis passes through thegaps or spaces separating said poles, for the purpose of placing all theinsulated wire of the armature under the direct influence of themagnet-poles, so as to avoid the use of inactive wire.

7. In a dynamo-electric machine, a spherical inclosed armatureconsisting, essentially, of a core of iron, W, of suitable construction,

with insulated-wire coils surrounding the same, and in turn surroundedas far as practicable by the field-magnet coils, for the purpose ofobtaining the maximum inductive effect in the insulated wire of thearmature, substantially as described.

8. In a dynamo-electric machine, a magnet-frame consisting of hollowshells N and flanges F F, as described, and with connectin g-bars B Bbetween said flanges, the bars B B constituting an outer surroundingopen casing, in the center of which the armature revolves between theopposing faces of the magnet-shells N and as described.

9. A dynamo-electric machine in which the following elements ofeffective action are severally combined: magnetizing-coils surroundingand surrounded by iron masses placed so as to utilize both the internaland external magnetizing effects of said coils, said magnet--izing-coils surrounding and directly magnetizing both the field-magnetpoles and the armature-core; an inclosed armature wound with insulatedwire, upon which a convergence of magnetic force takes place at the sametime from all sides, thus placing the whole of the insulated wire in apowerful field, and an armature the coils of insulated wire of which areinductively acted upon by the currents in the surrounding field-magnetcoils.

ELIHU THOMSON.

Witnesses:

GEO. A. VAILLANT, J onN MYERs.

